It is known, as described in co-pending U.S. patent application Ser. No. 586,761 filed by H. R. Gerberich, Jr., on June 13, 1975, to oxidize C.sub.20 to C.sub.30 normal alkanes with air and then to oxidize the air oxidation product further with nitric acid to form fatty acids. The fatty acid product recovered from such a process, however, contains nitrogenous impurities arising during the nitric acid oxidation which are desirably removed for most end uses of the fatty acids. At present, there is no simple and economical way known to remove substantially all of such nitrogen-containing impurities. It is known that some of these nitrogen-containing impurities may be converted to easily removable amine compounds by hydrogenating the crude fatty acid product; however many of the nitrogen-containing impurities are not converted to amines by hydrogenation, but remain in a difficulty-removable form.
It is thus an object of the present invention to produce an improved method of producing a fatty acid product from C.sub.20 to C.sub.30 normal alkanes involving a nitric acid oxidation, which fatty acid product may be purified relatively easily in order to remove nitrogen-containing impurities therefrom. It is an additional object of the present invention to provide a new and improved method for producing a fatty acid product from C.sub.20 to C.sub.30 normal alkanes involving a nitric acid oxidation, which fatty acid product is relatively free of nitrogen-containing impurities. Additional objects will become apparent from the following description of the present invention.